A major component of Oklahoma City's Core to Shore program is undergoing significant changes after it ran into enormous projected cost overruns.
The proposed SkyDance Bridge, a pedestrian bridge spanning Interstate 40 that was to be an "iconic symbol of Oklahoma City's future" and serve as a linkage between the planned central park and promenade park, more than doubled from initial estimates, going from a $5.2 million project to a $12.8 million undertaking.
The reason for the estimated cost increase is because of several factors, according to an Oklahoma City Council memorandum, including, among other issues:
" Oklahoma Department of Transportation-recommended load capacity changes,
" bridge location adjustments, and
" estimated material cost increases from a "Buy American" clause the design company unsuccessfully sought to waive.
The estimated cost overruns have spurred the city to direct MKEC Engineering Consultants Inc. and Obelisk Engineering Inc. to redesign the structure. As a result, the cable-stay bridge designed to represent the state bird, the Scissor-tailed Flycatcher, will become a truss bridge with a self-supported bird sculpture.
On Tuesday, the city council will consider a measure to pay an additional $179,984 to designers to change the bridge, putting total design costs around $1.6 million.
The original cable-stay design had the bridge supported by cables running from two of the structure's 18-story towers, but the new design would eliminate those cables for a normal truss pedestrian bridge with the bird sculpture towering above, said Dennis Clowers, public works director and city engineer.
However, he said, the bridge will remain similar in appearance to the original concept.
"It will still have basically the same look," Clowers said. "Someone driving down the highway or walking across it is not really going to notice."
One of the major sources of projected cost overruns was that the bridge model and estimate presented were based on design concepts that are no longer in effect. The new requirements recommended by ODOT, which were brought into the design process as a third-party design reviewer, require a much heavier load capacity.
"They were legitimate concerns," Clowers said of ODOT's recommendations.
In addition, a second bridge north of the SkyDance that was in the first set of plans will be listed as an "add-alternate," which means it will be built only if the company winning the construction bid can include it for under the total bid amount, he said.
If the north bridge cannot be constructed, a ramp will be put in place instead, the council's memo states.
The redesigned bridge, which was to be located near S.W. Ninth Street and Harvey Avenue, has an estimated construction cost of $6.8 million, an amount that puts the project right against its budget threshold.
"The construction budget for this project is very tight," the city council memo states. "Extraordinary design effort will be required to meet this construction budget."
The memo goes on to note that inflation and material cost changes were not included in the $6.8 million estimate.
Clowers said the project will likely begin and be completed next year, so inflation or other cost changes may not be much of a factor.
"From what we can tell, that's not going to be the case," he said of possible future cost overruns. "If it is, we have to find additional funds or will have to change the design of the bridge again." "Clifton Adcock
above The proposed SkyDance Bridge, which is now being redesigned.